1. Field of the Invention
The present disclosure relates generally to the field of firearm components. More specifically, the present invention relates to a bolt carrier adaptable to be used with a firearm.
2. Description of Related Art
A number of firearms operate based on a gas blowback system. One such firearm is the M-16, M-4, and AR-15 family of firearms. The AR-15 is based on the AR-10, which was designed by Eugene Stoner, Robert Fremont, and L. James Sullivan of the Fairchild ArmaLite Corporation in 1957. Today, there are numerous variants of the AR-15 that are manufactured by a number of companies. The AR-15 and its various related derivative platforms are used by civilians, law enforcement personnel, and military forces around the world.
During normal operation of a semiautomatic AR-15 style rifle, when a round is fired, gas from the burning propellant forces the bullet through the barrel. Before the bullet leaves the barrel, a portion of the gas enters a gas port in the upper part of the barrel under the front sight (or gas block). The gas port directs gas through a portion of the front sight (or gas block) and into the gas tube, which directs the gas into a cylindrical gas aperture 42 of the bolt carrier key 40, between the bolt carrier 20 and the bolt 50 and drives the bolt carrier 20 rearward.
The buffer, which is pushing on the rear of the bolt carrier group 10, is forced rearward by the bolt carrier group 10 compressing the recoil spring. During this rearward movement, a cam pin track or slot 22 in the upper portion of the bolt carrier 20 acts on the bolt cam pin 30, translating the rearward linear movement of the carrier into rotational movement, thereby rotating the cam pin 30 and bolt 50 clockwise so that the bolt locking lugs are unlocked from the barrel extension locking lugs. As the rearward movement of the bolt carrier group 10 continues, the empty cartridge case is extracted from the chamber, and ejected through the ejection port.
As the bolt carrier group 10 clears the top of an inserted magazine and the empty cartridge case is expelled, a new round is pushed into the path of the bolt 50 by the upward thrust of the magazine follower and spring.
As the bolt carrier group 10 continues to move rearward, it overrides the hammer and forces the hammer down into the receiver, compressing the hammer spring, and allowing the rear hook of the hammer to engage with the hammer disconnect.
When the bolt carrier group 10 reaches its rearmost position (when the rear of the buffer contacts the rear of the buffer tube), the compressed recoil spring expands, driving the buffer assembly forward with enough force to drive the bolt carrier group 10 forward, toward the chamber, initiating chambering of the waiting round from the magazine into the chamber.
The forward movement of the bolt 50 ceases when the locking lugs pass between the barrel extension locking lugs and the round is fully chambered. When the bolt carrier 20 enters the final portion of its forward movement, the bolt cam pin 30 emerges from the cam pin guide channel in the upper receiver and moves along the cam pin slot 22, rotating the bolt 50 counterclockwise. This rotation locks the bolt 50 to the barrel extension (by interaction of the bolt locking lugs and the barrel extension locking lugs). The locking of the bolt 50 completes the cycle of operation and, when the trigger is released, the rear hammer hook hammer slips from the disconnect and the front hammer hook is caught by the sear of the trigger. The firearm is then ready to be fired again.
Any discussion of documents, acts, materials, devices, articles, or the like, which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.